Polyester-based adhesive composition, polyester-based adhesive, adhesive film, adhesive composition for heat-resistant adhesive film, heat-resistant adhesive film for masking, and method of using heat-resistant adhesive film for masking

Abstract

To provide a polyester-based adhesive composition, a polyester-based adhesive, an adhesive film, an adhesive composition for heat-resistant adhesive film, a heat-resistant adhesive film for masking, and a method of using the heat-resistant adhesive film for masking, in which change over time such as increase of adhesive force is little even with use under a high temperature environment.SOLUTION: A polyester-based adhesive composition contains a polyester-based resin having a carboxyl group derived from an at least trivalent carboxylic acid and / or acid anhydride thereof in a side chain and / or terminal of a molecule.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyester-based pressure-sensitive adhesive composition, a polyester-based pressure-sensitive adhesive, a pressure-sensitive adhesive film, and a heat-resistant Adhesive composition for adhesive film, heat-resistant adhesive film for masking, heat-resistant adhesive film for masking For more details on how to use the film, please refer to the instructions for using it in a high-temperature environment while it is attached to the adherend. Even if the adhesive is used in a protective layer, contamination such as adhesive remaining on the adherend may occur when the adhesive is peeled off. Heat-resistant adhesive film for masking that is resistant to heat and has little change in adhesive strength over time, For polyester-based adhesive compositions, polyester-based adhesives, adhesive films, and heat-resistant adhesive films The present invention relates to a pressure-sensitive adhesive composition and a method for using a heat-resistant pressure-sensitive adhesive film for masking. [Background technology]

[0002] Conventionally, polyester resins are produced by combining a polycarboxylic acid component and a polyol component. It is known that this method provides excellent chemical resistance, mechanical strength, etc., and Such adhesives are also useful in the field of adhesives. For example, Patent Documents 1 to 3 disclose such adhesives. The one in Patent Document 1 is a comparison of the weight average molecular weight of the polyester resin as the main component. By reducing the viscosity at 23°C to a specified value or less, the It is said to achieve good coating properties at temperatures around room temperature without the need for dilution. There are.

[0003] In addition, the compound of Patent Document 2 contains less than half of the total carboxylic acid components as a carboxylic acid component. Aromatic dicarboxylic acids are used, and glycols having hydrocarbons in the side chains are used as polyhydric alcohol components. By using coal, an adhesive with excellent adhesive properties, heat resistance, and mechanical strength can be obtained. It is said that this is possible.

[0004] The one in Patent Document 3 is a polyester containing a polycarboxylic acid component and a glycol component. The main chain is a terpolymer, and a compound with one carboxyl group and one acid anhydride group is attached to the end. By using a polyester copolymer containing the hydroxybenzoates, it is possible to obtain a molecular weight in a desirable range and a high acid value. As a result, the adhesiveness and cohesion, which are contradictory properties, are maintained while suppressing gelation. It is also said to improve sexuality. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2011 / 081163 [Patent Document 2] Japanese Patent Application Laid-Open No. 2007-45914 [Patent Document 3] Japanese Patent Application Laid-Open No. 2013-75965 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the coating composition of Patent Document 1 cannot achieve good coating properties in a temperature range around room temperature. However, due to its low cohesive strength, it is very difficult to handle and is not suitable for practical use. In particular, since it lacks stiffness immediately after coating, it is vulnerable to dents and the yield rate during adhesive manufacturing is poor. In addition, in applications where heat resistance is required, the adhesive strength increases too much, When used as a heat-resistant adhesive film for packaging, the adhesive may remain on the adherend, causing contamination. Furthermore, the material disclosed in Patent Document 2 has excellent adhesive properties, heat resistance, and mechanical strength. Although it produces an excellent adhesive, it is not suitable for use as a masking film for protecting the surface of the adherend. When used in a high-temperature environment, there is room for further improvement in the peelability after use. The one disclosed in Patent Document 3 suppresses gelation while achieving the opposite property. Although this improves both adhesiveness and adhesion, it is an adhesive. It is not an adhesive that is intended to be peeled off, so it is not suitable for use as a masking agent to protect the surface of the adherend. It is unsuitable for film.

[0007] In this invention, under such circumstances, adhesive strength is increased even when used in a high temperature environment. A polyester-based pressure-sensitive adhesive composition, a polyester-based pressure-sensitive adhesive, and an adhesive film that are less susceptible to changes over time such as deterioration due to adhesion film, adhesive composition for heat-resistant adhesive film, heat-resistant adhesive film for masking and masking The present invention aims to provide a method for using a heat-resistant adhesive film for packaging. [Means for solving the problem]

[0008] However, the present inventors have discovered that at least one of the side chains and terminals of the polyester resin molecule a carboxyl group derived from at least one of a trivalent or higher carboxylic acid and its acid anhydride; By using polyester resin that positively contains Therefore, a polyester-based pressure-sensitive adhesive composition capable of suppressing an increase in adhesive strength can be obtained. This led to the completion of the first invention. The present inventors have also discovered that a polyester resin having a product of acid value and weight average molecular weight of at least a specific value. By using a polymer that can suppress the increase in adhesive strength even when exposed to high temperature environments, The inventors have found that a polyester-based pressure-sensitive adhesive composition can be obtained, thereby completing the second invention.

[0009] That is, the present invention provides a polymer having a trivalent or higher carboxylic acid at least on one of the side chain and the terminal of the molecule. Polyesters containing carboxyl groups derived from at least one of acids and their acid anhydrides A first aspect of the present invention is a polyester-based pressure-sensitive adhesive composition containing a resin.

[0010] In addition, the present invention provides a polymer having an acid value (mgKOH / g) and a weight average molecular weight of 350,000 or more. A second aspect of the present invention is a polyester-based pressure-sensitive adhesive composition containing a polyester-based resin.

[0011] The present invention also provides a polyester-based adhesive obtained by crosslinking the polyester-based adhesive composition. The third aspect is an adhesive, and the adhesive film has an adhesive layer containing the polyester-based adhesive. The fourth aspect of the present invention is a heat-resistant adhesive film made using the polyester-based adhesive composition. The fifth aspect is a pressure-sensitive adhesive composition for heat-resistant adhesive films. The sixth aspect of the present invention provides a heat-resistant adhesive film for masking having an adhesive layer for a heat-resistant adhesive film comprising the following: The heat-resistant adhesive film for masking is then subjected to a treatment to reduce the adhesive strength of the adhesive layer for the heat-resistant adhesive film. and a step of attaching the heat-resistant masking adhesive to an adherend using the heat-resistant masking adhesive attached to the adherend. The film is heated to 120°C or higher together with the adherend, and the mass that has passed through the heating process is then and peeling the heat-resistant adhesive film for masking from the adherend. The seventh point is how to use the adhesive film.

[0012] Furthermore, the present invention provides a polymer having an acid value of 5 mgKOH / g or more and a weight average molecular weight of 2,000 or more. A polyester resin containing an epoxy crosslinking agent and an alcohol solvent. An eighth aspect of the present invention relates to a pressure-sensitive adhesive composition.

[0013] In general, in the production of polyester resins, the terminals of the molecules are made to be hydroxyl groups, In most cases, acidic groups such as carboxyl groups are not left behind. If acidic groups remain, the polyester resin This is because hydrolysis is accelerated. Therefore, it is not suitable for adhesive applications where environmental durability is required. In this case, the design is made to leave as few acidic groups as possible. However, in the first invention, the acidic group is intentionally placed at the end of the molecule or on the side chain within the molecule. By actively allowing the carboxyl groups present and using these acidic groups as crosslinking points, It achieves a high cross-linking density, and even when exposed to high temperatures, the adhesive strength increases and it becomes difficult to peel off. It is possible to obtain a polyester-based pressure-sensitive adhesive composition that can suppress the above-mentioned problems. I found it. In the second invention, the relationship between the acid value and the weight average molecular weight of the polyester resin is considered. For this purpose, a polyester resin with a high acid value and a large weight average molecular weight is used. If the product of the molecular weight is above a certain level, the adhesive strength will not increase even if exposed to a high temperature environment. It is possible to obtain a polyester-based pressure-sensitive adhesive composition that can prevent the adhesive from becoming difficult to peel. I discovered that it was possible. [Effects of the Invention]

[0014] The polyester-based pressure-sensitive adhesive composition of the first invention has a structure in which at least one of the side chains and the terminals of the molecule a carboxy group derived from at least one of a trivalent or higher carboxylic acid and its acid anhydride; The polyester resin contains the above-mentioned The polyester-based pressure-sensitive adhesive composition of the second invention has an acid value (mgKOH / g) and a weight average It contains a polyester resin with a molecular weight product of 350,000 or more. Therefore, as mentioned above, even when exposed to high temperature environments, the increase in adhesive strength is suppressed, and adhesive strength It is possible to suppress the change over time. Therefore, the polyester-based pressure-sensitive adhesive composition of the present invention is crosslinked. Even when used in a high temperature environment, the adhesive will not remain on the adherend, causing contamination. It is suitable for use as an adhesive layer in heat-resistant masking films that are resistant to heat and have little change in adhesive strength over time. I can. DETAILED DESCRIPTION OF THE INVENTION

[0015] The configuration of the present invention will be described in detail below, but these are examples of preferred embodiments. It is something.

[0016] The polyester-based pressure-sensitive adhesive composition of the first invention (hereinafter, the polyester-based pressure-sensitive adhesive composition is referred to as "adhesive") The compound (sometimes abbreviated as "composition") is a compound having a trivalent or higher valence group at least on the side chain or terminal of the molecule. a poly(ethylene glycol) having a carboxyl group derived from at least one of the carboxylic acid and its acid anhydride; It is characterized by containing an ester-based resin. The pressure-sensitive adhesive composition of the second invention has a product of the acid value (mgKOH / g) and the weight-average molecular weight of 3. It is characterized by containing a polyester resin with a molecular weight of 50,000 or more. The components constituting the polyester-based pressure-sensitive adhesive composition of the present invention will be described below in order. This will be explained next.

[0017] <Polyester resin> The polyester resin used in the present invention is a polycarboxylic acid and its acid anhydride (hereinafter referred to as " The copolymerization of a copolymer containing a polyol and a carboxylic acid This is what can be obtained. General polyester resins contain polycarboxylic acids, usually dicarboxylic acids. In the first invention, in addition to divalent carboxylic acids, trivalent or higher carboxylic acids are used. By using carboxylic acids, at least one of the side chains and terminals of the polyester resin molecule can be On the other hand, it is characterized in that it has a carboxy group derived from the above-mentioned trivalent or higher carboxylic acids. This is a sign. In the second invention, the product of the acid value and the weight average molecular weight of the polyester resin is It is characterized by using a specific or higher acid value, i.e., a high weight average molecular weight. This is what is done.

[0018] [Polycarboxylic acids] Examples of dicarboxylic acids used as constituent raw materials for polyester resins include: , malonic acids, dimethylmalonic acids, succinic acids, glutaric acids, adipic acids, trime Chiladipic acids, pimelic acids, 2,2-dimethylglutaric acids, azelaic acids, Acids of carboxylic acids, decanedicarboxylic acids, fumaric acids, maleic acids, itaconic acids, thiodicarboxylic acids Aliphatic dicarboxylic acids such as propionic acid, diglycolic acid, and 1,9-nonanedicarboxylic acid acids; Phthalic acids, terephthalic acids, isophthalic acids, benzylmalonic acids, diphenic acids, 4,4'-oxydibenzoic acids, 1,8-naphthalenedicarboxylic acids, 2,3 -Naphthalenedicarboxylic acids, 2,7-naphthalenedicarboxylic acids, etc. aromatic dicarboxylic acids such as carboxylic acids; 1,3-Cyclopentanedicarboxylic acids, 1,2-Cyclohexanedicarboxylic acids, 1 ,3-cyclopentanedicarboxylic acids, 1,4-cyclohexanedicarboxylic acids, 2,5 Alicyclic dicarboxylic acids such as norbornanedicarboxylic acids and adamantanedicarboxylic acids ;etc. These dicarboxylic acids can be used alone or in combination of two or more.

[0019] In addition, trivalent or higher carboxylic acids used as constituent raw materials for polyester resins include Examples of the acid include trimellitic acids, pyromellitic acids, adamantanetricarboxylic acids, tricarboxylic acids, and the like. Among these, pyrophosphates are preferred because they can be easily made into high molecular weight and high acid value. A dianhydride of a tetracarboxylic acid such as mellitic dianhydride is preferably used. In terms of the properties, pyromellitic dianhydride is more preferred. These can be used alone or in combination of two or more.

[0020] The content of the trivalent or higher carboxylic acids is the ratio of the content to the divalent carboxylic acids. The molar ratio is trivalent or higher carboxylic acids / divalent carboxylic acids = 1 / 99 to 40 / 6. 0, particularly preferably 5 / 95 to 30 / 70, and further preferably 10 / 90~20 / 80. The content ratio of trivalent or higher carboxylic acids and divalent carboxylic acids ( When the molar ratio is within the above range, the glass transition temperature is kept low and an appropriate amount of acid value is imparted. Moreover, it is preferable in terms of ease of controlling the molecular weight.

[0021] In the present invention, among the above dicarboxylic acids, the dicarboxylic acid having a tacky feel is preferably used. Therefore, it is preferable to include an aliphatic dicarboxylic acid, specifically, for example, sebacic acid is preferred.

[0022] The content ratio of such aliphatic dicarboxylic acids to the total polycarboxylic acids is 5%. % or more, particularly preferably 50 to 99 mol %, and further preferably If the content is too low, the glass transition temperature of the resin may be higher than necessary. If the amount is too high, the adhesive performance tends to decrease. The solution stability of the adhesive tends to decrease.

[0023] Among the above dicarboxylic acids, aromatic dicarboxylic acids are preferred in terms of providing cohesive strength. It is also preferable to add an acid, and specifically, for example, isophthalic acid is preferably used. can be.

[0024] The content ratio of such aromatic dicarboxylic acids to the total polycarboxylic acids is 1:1. % or more, particularly preferably 2 to 50 mol %, and further preferably 3 If the content is too low, crystallization is likely to occur, and adhesion is reduced. If the amount is too large, the glass transition temperature will increase and the adhesive will become less stable. Performance tends to decrease.

[0025] In the present invention, from the viewpoint of adhesive properties, aromatic dicarboxylic acids are used as polycarboxylic acids. It is also preferable to use aromatic dicarboxylic acids and aliphatic dicarboxylic acids in combination. The content ratio (molar ratio) of aliphatic dicarboxylic acids is aromatic dicarboxylic acids / aliphatic dicarboxylic acids. Carboxylic acids=1 / 99 to 49 / 51 is preferred, and particularly preferred is 5 / 95 to Within this range of content ratio, the balance between the glass transition temperature and cohesive strength is This is preferable because it is easy to obtain.

[0026] [Polyol] The polyols used as constituent raw materials for polyester resins include, for example, Examples include aliphatic diols with a chain structure, other dihydric alcohols, and trihydric or higher polyhydric alcohols. can be done. Examples of the linear aliphatic diol include ethylene glycol and diethylene glycol. alcohol, triethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,9-nonanediol, 1, 10-Decanediol, 1,12-Dodecanediol, Polyethylene Glycol, Polyethylene tetramethylene glycol and the like. Other dihydric alcohols include, for example, propylene glycol and dipropylene glycol. Cole, 2,4-dimethyl-2-ethylhexane-1,3-diol, 2-methyl-1, 3-Propanediol, 2,2-dimethyl-1,3-propanediol (neopentyl recall), 2-ethyl-2-butyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol 1,3-Butanediol, 3-Methyl-1,5- Branched structures such as pentanediol and 2,2,4-trimethyl-1,6-hexanediol Aliphatic diols having; 1,2-Cyclohexanedimethanol, 1,3-Cyclohexanedimethanol, 1,4 -Cyclohexanedimethanol, spiroglycol, tricyclodecane dimethanol, Damantanediol, 2,2,4,4-tetramethyl-1,3-cyclobutanediol, etc. Alicyclic diols; 4,4'-thiodiphenol, 4,4'-methylenediphenol, bisphenol S, Bisphenol A, bisphenol fluorene, 4,4'-dihydroxybiphenyl, o -, m- and p-dihydroxybenzene, 2,5-naphthalenediol, p-xylene Aromatic diols such as diols; and ethylene oxide, propylene oxide, etc. doped adducts; etc. Examples of trihydric or higher polyhydric alcohols include pentaerythritol, dipentaerythritol, Triethoxycaprylyl, Tripentaerythritol, Glycerin, Trimethylolpropane, Trimethylol Examples of the methyl alcohol include methyl ethane, 1,3,6-hexanetriol, and adamantanetriol. do.

[0027] Among these, polyisocyanates having a branched structure are preferred because they disrupt crystallinity and improve solution stability. From the viewpoint of versatility, it is preferable to use an aliphatic diol having a branched structure. In particular, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2 It is preferred to use 2-ethyl-1,3-propanediol.

[0028] Furthermore, the straight-chain aliphatic diols have the advantage of lowering the glass transition temperature (Tg) and improving adhesive performance. It is preferable to use ethylene glycol, which has flexibility and excellent adhesive properties. It is preferable to use a linear aliphatic diol other than diethylene glycol, and particularly diethylene glycol. ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexadecyl It is preferable to use phenyl diol, which reduces the crystallinity of the resin and provides better adhesion. In this respect, it is preferable to use diethylene glycol and 1,5-pentanediol.

[0029] The aliphatic diol having a branched structure is used in an amount of 10 to 100 mol based on the total amount of the polyol component. %, particularly 20 to 95 mol %, further 30 to 90 mol %, and especially 51 to 85 mol %. % is preferred.

[0030] The linear aliphatic diol is preferably present in an amount of 0 to 90 mol % based on the total amount of the polyol component. It is particularly preferably 5 to 80 mol %, further preferably 10 to 70 mol %, and particularly preferably 15 to 49 mol %. stomach.

[0031] The amount of other diols other than those mentioned above is preferably 50 mol % or less, particularly preferably 30 mol % or less, and more preferably 50 mol % or less. is preferably 10 mol % or less.

[0032] In the present invention, from the viewpoint of heat resistance, the content of the compound containing an ether bond is The content of the terephthalate resin is preferably 50% by weight or less, more preferably 20% by weight or less, and even more preferably 10% by weight or less. % by weight or less, and particularly 5% by weight or less is preferred.

[0033] The blending ratio of the polycarboxylic acids (including trivalent or higher carboxylic acids) and the polyol As for the amount of the polyol, it is preferable that the amount of the polyol is 1 to 3 equivalents per equivalent of the polycarboxylic acid. If the blending ratio of the polyol is too low, the polymer Quantification tends to be difficult, and if it is too high, the yield tends to decrease.

[0034] [Production of polyester resin] In general, polyester resins are made by arbitrarily selecting polycarboxylic acids and polyols. and the like in the presence of a catalyst by a known method, In the condensation reaction, an esterification reaction is carried out first, and then a polycondensation reaction is carried out. The polyester resin used in the present invention can also be produced by a method similar to this. can. The polyester resin used in the first invention has a structure in which at least one of the side chains and terminals of the molecule On the other hand, carboxylates derived from at least one of trivalent or higher carboxylic acids and their acid anhydrides are In the second invention, such a polyester resin can be used. It is preferable that: The polyester resin having the above characteristics is, for example, a polyester resin obtained by mixing a dicarboxylic acid and a polyol. A hydroxyl group-containing prepolymer with about 1 to 10 repeating units obtained by esterification of -, for example, the dianhydrides of tetracarboxylic acids, It can be produced by a method of chain extension using

[0035] That is, first, predetermined amounts of dicarboxylic acid and polyol are mixed without a solvent, and then the mixture is The mixture is charged into a reactor and heated to a temperature of usually 170 to 260°C. The esterification or transesterification reaction is carried out while removing the water or methanol that is generated. The mixing ratio of the dicarboxylic acid and the polyol is (molar ratio) is 1.05 to 1.65 moles of polyol per mole of dicarboxylic acid. It is more preferable that the amount of the hydroxybenzoate is 1.08 to 1.5 mol, and particularly preferably 1.1 to 1.3 mol. It is preferable that

[0036] In the above reaction, an esterification catalyst, an ester exchange catalyst, or other polymerization catalyst may be used as appropriate. Specifically, for example, tetraisopropyl titanate, tetrabutyl Titanium-based catalysts such as ruthenium iodide, antimony-based catalysts such as antimony trioxide, germanium dioxide Catalysts such as germanium catalysts, zinc acetate, manganese acetate, dibutyltin oxalate, etc. These may be used alone or in combination of two or more. Among these, the three-phase catalyst is the most suitable due to its balance between high catalytic activity and the color of the resulting reaction product. Antimony oxide, tetrabutyl titanate, germanium dioxide, and zinc acetate are preferred.

[0037] The amount of the catalyst to be added is 1 to 10,000 ppm based on the total copolymerization components (by weight). It is particularly preferable that the concentration is 10 to 5,000 ppm, and further preferably 20 to 3 If the amount is too small, the reaction tends to proceed insufficiently. However, if the amount is too large, there is no advantage such as shortening the reaction time, and side reactions tend to occur.

[0038] Next, the obtained hydroxyl group-containing prepolymer is mixed with a trivalent or higher carboxylic acid and its acid anhydride. A polyester resin can be obtained by chain extension through a ring-opening addition reaction using a compound. This can be done.

[0039] The hydroxyl group-containing prepolymer is chain-extended with a trivalent or higher carboxylic acid and its acid anhydride. The reaction is usually carried out at 230°C or less, preferably 60 to 210°C. The reaction is carried out at a temperature of 150 to 200°C, preferably 150 to 200°C. If the temperature is too high, the reaction will not proceed sufficiently, and if the temperature is too high, side reactions such as decomposition will occur. The pressure during the reaction is usually atmospheric pressure. The reaction time is usually 0.5 to 10 hours.

[0040] In the chain extension reaction, a trivalent carboxylic acid and its acid anhydride were used. In the case of tetravalent carboxylic acids, carboxyl groups derived from trivalent or higher carboxylic acids are likely to be introduced at the molecular end. When using carboxylic acids and their acid anhydrides, trivalent or higher carboxylic acids are used in the molecular side chains and terminals. This makes it easier to introduce a carboxyl group derived from carboxylic acids.

[0041] In addition, after producing the hydroxyl group-containing prepolymer, it is possible to Alternatively, a polycondensation reaction may be carried out, followed by the chain extension reaction. The compound containing the above carboxylic acid and its acid anhydride is used to depolymerize the side chain and And / or a carboxyl group may be introduced at the end.

[0042] It is not necessary to use a solvent in the above reaction, but if the viscosity of the reaction product is too high, In such cases, a suitable solvent may be used to facilitate stirring. Examples of the solvent include acetone, methyl ethyl ketone, and methyl isobutyl ketone. ketone solvents such as benzene, toluene, xylene, mesitylene, pseudocumene, and other aromatic solvents Examples include aromatic solvents, amide solvents such as dimethylformamide and dimethylacetamide. However, polyester resins, such as ester-based solvents and alcohol-based solvents, It is preferable not to use a solvent that may react with the

[0043] The reaction conditions for the polycondensation reaction are the same as those used in the esterification reaction. The reaction temperature is preferably 220 to 280°C, particularly preferably The reaction temperature is kept at 230-270°C, and the pressure in the reaction system is gradually reduced until the reaction is completed at 5 hPa or less. If the reaction temperature is too low, the reaction tends to proceed slowly. If the temperature is too high, side reactions such as decomposition tend to occur. The reaction time is 0.5 to 10 hours. The catalyst used in the chain extension reaction (polycondensation reaction) is an ester. It may be added after the esterification reaction is completed, or may be added in advance before the esterification reaction.

[0044] In addition to the above-mentioned method, the polyester resin can be produced by, for example, polyester or The terminal hydroxyl groups of the oligomer obtained by the esterification reaction are converted to an anhydride of a trivalent or higher carboxylic acid. It can also be obtained by adding a compound to replace the terminal hydroxyl groups with multiple carboxyl groups. Furthermore, polyester can be produced and depolymerized using a trivalent or higher carboxylic acid. It can also be obtained by adding multiple carboxy groups to the ends of the molecule. These methods may be carried out either alone or in combination. In this case, they may be performed simultaneously or at different times.

[0045] The polyester resin thus obtained has an acid value of 5 mgKOH / g or more. It is preferable that the KOH / g is 10 to 180 mgKOH / g, and more preferably 20 to 150 mgKOH / g. Of these, 30 to 120 mgKOH / g is even more preferable. 40 to 100 mgKOH / g is more preferable, and 50 to 80 mgKOH / g is particularly preferable. If the acid value is too low, the adhesiveness decreases and the effect of the present invention cannot be fully obtained. If the acid value is too high, the water resistance tends to decrease. The acid value of the polyester resin is determined by neutralization titration according to JIS K0070. It is something that can be done.

[0046] The acid value in the present invention is the content of carboxy groups in the polyester resin. The carboxyl group includes a carboxyl group neutralized with a basic compound. It also includes those in the form of a carboxylate ion. The acid value can be adjusted by, for example, adjusting the amount of trivalent or higher carboxylic acid and its acid anhydride, the reaction This can be achieved by adjusting the conditions (reaction time of the chain extension reaction) and the like.

[0047] The weight average molecular weight of the polyester resin is preferably 2,000 to 500,000. , more preferably 5,000 to 200,000, and particularly preferably 10,000 to 100 If the weight average molecular weight is too large, handling becomes difficult and a large amount of diluted solution is required. The need to use a chemical agent tends to reduce the economic efficiency. If the molecular weight is too small, the heat resistance, adhesive strength after heat resistance, and adhesive residue after peeling tend to deteriorate. .

[0048] The weight average molecular weight is calculated based on the molecular weight of standard polystyrene. A high-performance liquid chromatograph (Tosoh Corporation, "HLC-8320GPC") was used, and the column was TS. Kgel SuperMultipore HZ-M (exclusion limit molecular weight: 2×10 6 , reason Number of plates: 16,000 plates / unit, Filler material: styrene-divinylbenzene copolymer, Filling The measurement is performed using two in-line tubes (particle size: 4 μm).

[0049] The polyester resin used in the second invention has a product of acid value and weight average molecular weight of 350,000 or more. That is, it is important that the polyester resin has a high acid value and a weight average molecular weight of By using a polyester resin with a large diameter, cohesive strength is imparted to the adhesive, resulting in high Even when exposed to a hot environment, the adhesive strength does not increase and the adhesive strength does not change over time. The preferable range of this product is 450,000 to 10,000,000, and the particularly preferable range is 1,000,000 to It's 7 million. In addition, since general polyester resins have carboxyl groups only at the molecular terminals, Therefore, the acid value is low, and it is difficult to achieve a product of the acid value and the weight average molecular weight of 350,000 or more. The polyester resin has an acid value and a weight average molecular weight of 350,000 or more. The compound contains a trivalent or higher carboxylic acid and an anionic derivative thereof at least on the side chain or at the end of the molecule. It is preferable that the carboxyl group is derived from at least one of the waters.

[0050] The glass transition temperature (Tg) of the polyester resin is preferably −90 to 20° C. The temperature is particularly preferably from -80 to 0°C, and further preferably from -60 to -20°C. If the glass transition temperature (Tg) is too high, the adhesiveness of the resulting pressure-sensitive adhesive composition tends to decrease. On the other hand, if the glass transition temperature (Tg) is too low, the heat resistance and cohesive strength will decrease. There is a tendency for this to happen.

[0051] The glass transition temperature (Tg) was measured using a differential scanning calorimeter (DSC) manufactured by TA Instruments. The measurement temperature range is from -90°C to 100°C. The temperature rise rate is 10°C / min.

[0052] It is preferable that the polyester resin does not crystallize from the viewpoint of storage stability. Even in this case, it is preferable that the crystallization energy of the polyester resin is as low as possible. Preferably, it is usually 35 J / g or less, more preferably 20 J / g or less, particularly preferably 10 J / g or less. It is particularly preferably 5 J / g or less.

[0053] The pressure-sensitive adhesive composition of the present invention may contain optional components together with the polyester resin. Such optional components include, for example, a crosslinking agent. The adhesive crosslinks the vinyl resin to give it excellent cohesive strength, improving its performance as an adhesive. do.

[0054] <Crosslinking agent> The crosslinking agent is a compound having a functional group reactive with the functional group contained in the polyester resin. Any compound containing such a compound may be used. For example, a compound having reactivity with the carboxyl group in the polyester resin may be used. A compound containing a functional group having the above structure is used. Examples of such crosslinking agents include epoxy crosslinking agents, oxazoline crosslinking agents, and azides. Lysine-based crosslinking agents, melamine-based crosslinking agents, isocyanate-based crosslinking agents, carbodiimide-based crosslinking agents , amino-based crosslinking agents, metal-based crosslinking agents, etc.

[0055] Examples of the epoxy crosslinking agent include bisphenol A epichlorohydrin type crosslinkers. Epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl Glycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether 1,6-Hexanediol Diglycidyl Ether, Trimethylolpropane Triglyceride Sorbitol polyglycidyl ether, polyglycerol polyglycidyl Diglycerol Polyglycidyl ether, Pentaerythritol Polyglycidyl erythritol, Diglycerol Poly Glycidyl ether, 1,3'-bis(N,N-diglycidylaminomethyl)cyclohexyl and N,N,N',N'-tetraglycidyl-m-xylenediamine. "Tetrad C" manufactured by Ryo Gas Chemical Co., Ltd., "Tetrad X" manufactured by Mitsubishi Gas Chemical Co., Ltd., Synasia Commercially available products such as "S-610" manufactured by the company can also be used. Among them, 1,3'-bis(N ,N-diglycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl Di-m-xylylenediamine is preferred.

[0056] Examples of the oxazoline-based crosslinking agent include 2,2'-bis(2-oxazoline), 1,2-bis(2-oxazolin-2-yl)ethane, 1,4-bis(2-oxazoline) -2-yl)butane, 1,8-bis(2-oxazolin-2-yl)butane, 1,4-bis(2-oxazolin-2-yl)butane Bis(2-oxazolin-2-yl)cyclohexane, 1,2-bis(2-oxazoline- Aliphatic compounds such as 1,3-bis(2-oxazolin-2-yl)benzene and 1,3-bis(2-oxazolin-2-yl)benzene Or aromatic bisoxazoline compounds, 2-vinyl-2-oxazoline, 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, 2 -Isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline Phosphorus, addition-polymerizable oxazolines such as 2-isopropenyl-5-ethyl-2-oxazoline etc.

[0057] Examples of the aziridine crosslinking agent include tetramethylolmethane-tri-β-aziridine. Lysinyl propionate, Trimethylolpropane-tri-β-aziridinyl propionate N,N'-diphenylmethane-4,4'-bis(1-aziridinecarboxamide) ), N,N'-hexamethylene-1,6-bis(1-aziridinecarboxamide), etc. Examples include:

[0058] Examples of the melamine-based crosslinking agent include hexamethoxymethylmelamine, hexaethoxymethylmelamine, hexapropoxymethylmelamine, hexabutoxymethylmelamine , hexapentyloxymethylmelamine, hexahexyloxymethylmelamine, melamine Examples of the resin include polyethylene terephthalate resin.

[0059] Examples of the isocyanate crosslinking agent include 2,4-tolylene diisocyanate, 2,6-Tolylene diisocyanate, hydrogenated tolylene diisocyanate, 1,3-xylylene Diisocyanate, 1,4-xylylene diisocyanate, hexamethylene diisocyanate Anate, Diphenylmethane-4,4-diisocyanate, Isophorone diisocyanate , 1,3-bis(isocyanatomethyl)cyclohexane, tetramethylxylylenediiso cyanate, 1,5-naphthalene diisocyanate, triphenylmethane triisocyanate and the combination of these polyisocyanate compounds with polyisocyanates such as trimethylolpropane. The adducts of these polyisocyanate compounds and the biuret and isocyanate compounds of these polyisocyanate compounds are Examples include rate bodies. Among these, the isocyanurate of hexamethylene diisocyanate and 2,4-tolylene diisocyanate and / or 2,6-tolylene diisocyanate Adducts with trimethylolpropane, 2,4-tolylene diisocyanate and / or or 2,6-tolylene diisocyanate isocyanurate, tetramethylxylylene An adduct of a diisocyanate and trimethylolpropane is preferred.

[0060] Carbodiimide crosslinking agents include a carbodiimide group or its tautomer as a functional group. It is sufficient that the compound contains at least two or more cyanamide groups in a sexually related relationship in the molecule. For example, Nisshinbo Chemical's "Carbodilite V-02" and "Carbodilite V-02 -L2", "Carbodilite SV-02", "Carbodilite V-04", "Carbodila Carbodilite V-10, Carbodilite E-03A, Carbodilite E-02, Carbodilite Among them, from the viewpoint of adhesion between the adhesive layer and the substrate, Silylene skeleton, tolylene skeleton, diphenylmethane skeleton, tetramethylxylylene skeleton, etc. Those having an aromatic group are preferred, and in particular "Carbodilite V-04" and "Carbodilite "ToE-04" and the like are suitable.

[0061] Examples of amino crosslinking agents include hexamethylenediamine and triethanolamine. Examples include:

[0062] Examples of metal cross-linking agents include tetraethyl titanate and tetraethyl zirconate. , aluminum isopropionate and other metal alkoxides, and aluminum, iron, copper, zinc Lead, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, zirconium Acetylacetone, acetoacetate esters, and ethylenediaminetetraacetic acid of polyvalent metals such as nium Coordination compounds such as metal chelate compounds, acetate-ammonium complex salts, ammonium-carbonate nate complex salts and the like.

[0063] As the crosslinking agent, only one selected from these may be used, or two or more may be used in combination. It may be used.

[0064] In the present invention, the heat resistance of the adhesive film and the small amount of adhesive residue after peeling after heat resistance are important. Therefore, among the above, it is preferable to use an epoxy-based crosslinking agent as the crosslinking agent.

[0065] The content of the crosslinking agent depends on the amount of functional groups contained in the polyester resin, The resin can be appropriately selected depending on the molecular weight and intended use, but preferably, polyester resin 100 It is 2.5 to 30 parts by weight, particularly preferably 5 to 20 parts by weight, More preferably, it is 7 to 15 parts by weight. Conversely, if there is too much crosslinking agent, crosslinking will not occur, resulting in poor adhesion between the adhesive layer and the substrate, as well as poor water resistance. If the amount is too small, crosslinking will be insufficient, and adhesion and water resistance will tend to decrease.

[0066] In addition, the amount of functional groups (carboxy groups) in the polyester resin and the amount of functional groups in the crosslinking agent The molar ratio of polyester resin / crosslinking agent is preferably 100 / 1 to 100 / 600. It is preferable that the ratio is 100 / 20 to 100 / 200, and 100 / 40 to 100 / 150. It is more preferable that the ratio is 100 / 60 to 100 / 110, and particularly preferable that the ratio is 100 / 60 to 100 / 110. Conversely, if it is too high, crosslinking will not occur, and the adhesive layer and substrate will tend to have a lower adhesion and water resistance. If the amount is too small, cross-linking will be insufficient, and heat resistance and adhesive residue resistance after heat-resistant peeling will tend to decrease. do.

[0067] In the reaction between the polyester resin and the crosslinking agent, the functional groups that react with these components organic solvents that do not contain methyl ether, for example, esters such as ethyl acetate and butyl acetate, methyl ethyl ketone ketones such as methyl isobutyl ketone, aromatic compounds such as toluene and xylene, methanoic Alcohols such as alcohol, ethanol, 1-propanol, 2-propanol, and butanol These organic solvents can be used alone or in combination of two or more. This can be done.

[0068] In the present invention, among the above organic solvents, a liquid containing a polyester resin and a crosslinking agent is used. In order to extend the pot life when blended with the above, it is preferable to contain an alcohol solvent. It is particularly preferred that the solvent contains 2-propanol. Here, the organic solvent is preferably a mixed solvent containing an alcohol-based solvent, The content of such an alcohol-based solvent in the organic solvent is preferably 10 to 80% by weight. In particular, 20 to 70% by weight, and further preferably 30 to 60% by weight.

[0069] Generally, polyester resins with high acid values ​​and large weight average molecular weights and epoxy crosslinkers are used. When the polyester resin composition contains the above-mentioned additives, the pot life tends to be shortened. When preparing a liquid containing alcohol-based resin and epoxy-based crosslinking agent, the alcohol-based solvent is included. This can extend the pot life. That is, the pressure-sensitive adhesive composition of the third invention has an acid value of 5 mgKOH / g or more and a weight average molecular weight of Contains polyester resin with a mass of 2,000 or more, epoxy crosslinking agent, and alcohol solvent This is what we do.

[0070] The pressure-sensitive adhesive composition of the present invention may contain, as an optional component, other than the crosslinking agent, which does not impair the effects of the present invention. Insofar as it does not cause any problem, antioxidants, hydrolysis inhibitors, urethanization catalysts, catalytic action inhibitors, Additives such as softeners, UV absorbers, stabilizers, antistatic agents, tackifiers, etc., and other inorganic or Alternatively, powder or particulate additives such as organic fillers, metal powders, pigments, etc. may be blended. These can be used alone or in combination of two or more.

[0071] <Antioxidants> The pressure-sensitive adhesive composition of the present invention contains an antioxidant, which makes it possible to This can prevent the molecular weight of the polyester resin from decreasing, improving heat resistance and This results in excellent resistance to adhesive transfer onto the adherend. The antioxidant used in the present invention includes, for example, a hindered phenol-based antioxidant. amine-based antioxidants, sulfur-based antioxidants, phosphoric acid-based antioxidants, etc. At least one selected from amine-based antioxidants and phosphoric acid-based antioxidants Antioxidants made of hindered phenol compounds are preferred, and particularly preferred are antioxidants made of hindered phenol compounds. Examples of hindered phenol antioxidants include those in which a phenolic hydroxyl group is bonded. At least one of the carbon atoms adjacent to the carbon atom on the aromatic ring has a tertiary butyl group or the like. Antioxidants that have a hindered phenol structure with a large, hindered group attached include .

[0072] The content of the antioxidant is preferably 0.0 parts by weight based on 100 parts by weight of the polyester resin. It is 1 to 10 parts by weight, more preferably 0.03 to 8 parts by weight, and even more preferably 0 0.05 to 5 parts by weight. If the content is too low, adhesive residue tends to be left on the adherend, and if it is too high, If the adhesive strength is too high, the adhesive properties tend to decrease.

[0073] In addition to the above additives, the adhesive composition of the present invention may contain other components, such as adhesive constituents, which are contained in the raw materials for manufacturing the adhesive. It may contain small amounts of impurities that may be present.

[0074] The polyester-based pressure-sensitive adhesive of the present invention (hereinafter sometimes abbreviated as "pressure-sensitive adhesive") is The adhesive composition is crosslinked (cured). The adhesive strength of the object is increased, resulting in an adhesive having the desired adhesive strength.

[0075] The gel fraction of the adhesive must be 70% by weight or more in terms of durability and adhesive strength. is preferred, particularly preferably 80 to 99% by weight, and further preferably 90 to 98% by weight. If the gel fraction is too low, the cohesive force decreases, which tends to reduce the heat resistance. If the gel fraction is too high, there is a concern that the adhesive strength will be too low due to an increase in cohesive force.

[0076] The gel fraction is a measure of the degree of crosslinking and is calculated, for example, by the following method. That is, a pressure-sensitive adhesive layer is formed on a polymer film (e.g., PET film) that serves as a base material. The adhesive film (without a separator) is then placed on a 200 mesh SUS metal Wrapped in a net and immersed in toluene at 23°C for 24 hours, the weight of the adhesive layer before immersion in toluene was The weight percentage of the undissolved adhesive component remaining in the wire mesh is the gel fraction. The weight of the material is subtracted.

[0077] The pressure-sensitive adhesive film of the present invention comprises a support substrate having the pressure-sensitive adhesive of the present invention on one or both sides thereof. and in particular, a heat-resistant adhesive film for masking. It is suitable as a In the present invention, the term "film" includes "sheet" and "tape." do.

[0078] <Adhesive film> The adhesive film can be produced, for example, as follows. The adhesive film was manufactured in accordance with a known general adhesive film manufacturing method. For example, the pressure-sensitive adhesive composition can be applied to one surface of a substrate and then dried. A release sheet is attached to the surface of the adhesive layer (the surface opposite to the surface that contacts the substrate), and if necessary, If necessary, by curing, a pressure sensitive adhesive sheet containing a pressure sensitive adhesive formed by crosslinking the pressure sensitive adhesive composition can be formed on a substrate. Thus, the adhesive film of the present invention having the adhesive layer is obtained.

[0079] The pressure-sensitive adhesive composition is applied to a release sheet and dried to form a pressure-sensitive adhesive layer. By attaching a substrate to the surface (the side opposite to the surface that comes into contact with the release sheet) and curing it as necessary, The adhesive film of the present invention is obtained.

[0080] When using the obtained adhesive film, the release sheet is peeled off from the adhesive layer, and the adhesive The layer and the adherend are attached to each other.

[0081] Examples of the substrate include polyethylene naphthate, polyethylene terephthalate, Polybutylene terephthalate, polyethylene terephthalate / isophthalate copolymer, etc. polyester resins; Polyolefin resins such as polyethylene, polypropylene, and polymethylpentene; Polyethylene fluorides such as polyvinyl fluoride, polyvinylidene fluoride, and polyethylene fluoride resin; Polyamides such as nylon 6 and nylon 6,6; Polyvinyl chloride, polyvinyl chloride / vinyl acetate copolymer, ethylene-vinyl acetate copolymer vinyl such as ethylene-vinyl alcohol copolymer, polyvinyl alcohol, vinylon polymers; Cellulose-based resins such as cellulose triacetate and cellophane; Polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, polyacrylic acrylic resins such as butyl acrylate; Polystyrene; Polycarbonate; Polyarylate; Polyimide; Cycloolefin Poly Synthetic resin films such as polymers; aluminum, copper, iron metal foil; fine paper, glassine paper, etc. Examples of the substrate include paper, woven fabrics and nonwoven fabrics made of glass fiber, natural fiber, synthetic fiber, etc. can be used as a single layer or as a multi-layer structure in which two or more types are laminated.

[0082] Among these, substrates made of polyethylene terephthalate and polyimide are particularly preferred. Polyethylene terephthalate is preferred because it has excellent adhesive properties with the pressure-sensitive adhesive layer. In particular, polyethylene terephthalate having a metal thin film layer is preferable for the substrate and the adhesive layer. It has excellent adhesive strength to the substrate, and the metal thin film layer does not corrode, so the substrate can be kept stable. This is preferable in that the effects of the adhesive used in the present invention can be significantly exhibited.

[0083] The thickness of the substrate is preferably, for example, 1 to 1,000 μm, and particularly preferably is preferably 2 to 500 μm, more preferably 3 to 300 μm.

[0084] Examples of the release sheet include the various synthetic resin sheets, paper, cloth, and the like exemplified above as the substrate. Nonwoven fabrics that have been treated with a release agent can be used. Among them, silicone-based synthetic resins are preferred. It is preferable to use a phosphate.

[0085] The pressure-sensitive adhesive composition can be applied to a substrate or a release sheet by, for example, gravure coating. Roll coater, reverse roll coater, kiss roll coater, dip roll coater coater, bar coater, knife coater, spray coater, comma coater, etc. do.

[0086] As for the drying conditions after coating the pressure-sensitive adhesive composition, the drying temperature is preferably 60 to 140°C. The drying temperature is preferably 80 to 120° C., and more preferably 80 to 120° C. The drying time is preferably 0.5 to 30 minutes. The time is preferably 1 to 5 minutes.

[0087] When the pressure-sensitive adhesive composition is cured, the curing conditions are usually room temperature ( The incubation time is usually 1 to 30 days, for example, at 23°C for 1 to 2 days. The incubation can be carried out under conditions such as 0 days, preferably 3 to 14 days at 23°C, or 1 to 10 days at 40°C. preferable.

[0088] The thickness of the pressure-sensitive adhesive layer is preferably 2 to 500 μm, more preferably 5 to 2 The thickness of the pressure-sensitive adhesive layer is preferably 100 to 100 μm, and more preferably 10 to 100 μm. If the thickness is too thick, it will be difficult to apply evenly and the adhesive strength will tend to decrease. There is a tendency for defects such as air bubbles to form in the film. is preferably 50 μm or more.

[0089] The thickness of the adhesive layer was measured using a Mitutoyo ID-C112B adhesive film. The thickness of the entire film is measured by subtracting the thickness of the components other than the adhesive layer. This is the value that is more desirable.

[0090] Furthermore, such an adhesive film may, if necessary, be provided with a release sheet on the outside of the adhesive layer, The adhesive layer may be protected. In this case, by applying a release treatment to the surface of the substrate opposite to the adhesive layer, the release-treated surface can be utilized. It is also possible to protect the adhesive layer by using a film.

[0091] The pressure-sensitive adhesive film of the present invention can be used to bond various members. However, it is preferable to use it as a masking film for surface protection of adherends. The adhesive layer on the film prevents the adhesive strength from increasing even when exposed to high temperature environments. Even if the masking film is used in a high temperature environment, the adhesive layer (adhesive This is because it is less likely to cause contamination such as residual adhesive (agent) remaining on the adherend.

[0092] Therefore, the pressure-sensitive adhesive film of the present invention is particularly excellent in heat resistance, and is therefore suitable for use as a masking film. It can be suitably used as a heat-adhesive film. For example, the heat-resistant adhesive film for masking of the present invention can be used to The heat-resistant adhesive masking film attached to the adherend is then attached to the adherend. The entire body is heated to over 120°C, and the heat-resistant adhesive masking film is placed on top. By peeling it off from the adherend, masking is performed accurately and the adhesive layer is not contaminated. Therefore, an undamaged adherend can be obtained.

[0093] The heat-resistant adhesive film according to the present invention is suitable for, for example, circuit boards such as FPC boards and ITO transparent electrodes. As a heat-resistant adhesive film for temporary surface protection to protect layers, or during manufacturing It is a heat-resistant adhesive film for temporary fixing to hold and reinforce products during processing. and can be used.

[0094] The adherend to which such a heat-resistant adhesive film is to be attached includes, for example, the following materials: Examples of materials include base materials. Metal plates include aluminum, copper, iron, stainless steel, magnesium, nickel, titanium, etc. or metal foil; Polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate polyethylene terephthalate / isophthalate copolymer, ester acrylate, etc. Polyester resin; Polyethylene, chlorinated polyethylene, chlorosulfonated polyethylene, ethylene propane Pyrene rubber, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, Ethylene-isobutyl acrylate copolymer, ethylene-acrylic acid copolymer, ethylene -methacrylic acid copolymers, ionomers, polypropylene, polyallomer polybutylene, Polyolefin resins such as polymethylpentene; Polyvinyl fluoride, Polyvinylidene fluoride, Polytetrafluoroethylene, Ethylene-tetrafluoroethylene Polyfluorinated ethylene resins such as fluorinated ethylene copolymers; Polystyrene, poly-α-methylstyrene, acrylonitrile-styrene copolymer, acrylic Acrylonitrile-butadiene-styrene copolymer, acrylonitrile-styrene-acrylate Copolymer; Polymethyl methacrylate, polyethyl methacrylate, polyethyl acrylate, polyacrylic Polyalkyl (meth)acrylates such as butyl acrylate and methyl methacrylate-styrene acrylic resins such as copolymers, methyl methacrylate-α-methylstyrene copolymers; Polyvinyl chloride, plasticized polyvinyl chloride, ABS modified polyvinyl chloride, post-chlorinated polyvinyl chloride Vinyl chloride, polyvinyl chloride-acrylic resin alloy, vinyl chloride-propylene copolymer, salt vinyl chloride-vinyl acetate copolymer, polyvinylidene chloride and other polyvinyl chloride polymers and Derivatives of; Polyvinyl acetate, polyvinyl alcohol, polyvinyl formal, polyvinyl butyrate ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, vinylon Polyvinyl acetate, etc., and its derivatives; Polyvinyl methyl ether, polyvinyl methyl ketone; Polyformaldehyde, acetal copolymer, polyethylene oxide, polypropylene Polyphenylene oxide, chlorinated polyether, phenoxy resin, polyphenylene oxide, etc. Polyether; Polytetrafluoroethylene, polychlorotrifluoroethylene, tetrafluoroethylene Polyethylene-hexafluoropropylene copolymer, polyvinylidene fluoride, chlorotrifluoroethylene Fluorinated resins such as ethylene-vinylidene fluoride copolymers; Polycarbonate, Polycarbonate ABS alloy; Nylon, nylon-6, nylon-6,6, nylon-6 / 6,6 copolymer, nylon Nylon (polypropylene) such as nylon-6,10, nylon-6,12, nylon-11, nylon-12 riamides); Butadiene-styrene copolymers, butadiene-based plastics; Polyimide and its derivatives, polysulfone, polyphenylene sulfide, high acrylic Nitrile copolymer; Silicone resins, semi-inorganic and inorganic polymers; Phenols such as phenolic resin, phenol-furfural resin, and modified phenolic resin Resins and their derivatives; Forma resins such as furan resin, xylene resin, aniline resin, acetone formaldehyde resin Phosphorus resin; Unsaturated polyester and alkyd resins; Bisphenol-type epoxy resin, epoxy resin composite material, alicyclic epoxy resin, epoxy Epoxy resins such as novolac, biphenyl-type epoxy resins, and epoxy acrylates; Polyurethanes such as polyurethane, urethane foam, and urethane acrylate; Diallyl phthalate resin, triallyl cyanurate resin, polyallylsulfone, allyl Allyl resins such as diglycol carbonate, polyallyl ether, and polyarylate; Cellulose-based plastics, cellulose acetate, cellulose propionate, cell Cellulose acetate butyrate, ethyl cellulose, nitrocellulose and celluloid Lubricant resin.

[0095] In particular, heat-resistant adherend materials include aluminum, copper, iron, stainless steel, and magnesium. Metal plates or foils such as nickel, titanium, etc.; Polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate polyethylene terephthalate / isophthalate copolymer, ester acrylate, etc. Polyester resin; Polyvinyl fluoride, Polyvinylidene fluoride, Polytetrafluoroethylene, Ethylene-tetrafluoroethylene Polyfluorinated ethylene resins such as fluorinated ethylene copolymers; Polyimides and their derivatives; Bisphenol-type epoxy resin, epoxy resin composite material, alicyclic epoxy resin, epoxy Novolac, biphenyl type epoxy resin, epoxy acrylate and other epoxy resins are preferred. It is often used.

[0096] Uses of the heat-resistant adhesive film obtained using the pressure-sensitive adhesive composition for heat-resistant adhesive films of the present invention For example, carrier films for processing printed circuit boards, especially flexible printed circuit boards; Protective film for preventing curling, wrinkling and contamination of films and foils that are heated; Protective film for solder plating on printed circuit boards; Insulating and heat-resistant protective films for heat-resistant transformers, etc. Masking film for use during the solder reflow process of electronic circuit boards; Various temporary fixing and component protection films; Film for sealing through-holes; Examples of applications include surface protection films for touch panel-related components such as ITO transparent electrode layers. It can be widely used for masking and temporary fixing applications that require heat resistance. A heat-resistant adhesive film for masking is preferred.

[0097] The pressure-sensitive adhesive composition for a heat-resistant adhesive film of the present invention is used to produce the heat-resistant adhesive film of the present invention. The method of using the thermal adhesive film includes, for example, a heating step during the manufacturing process of the adherend. In this case, a method for temporarily protecting the surface of the adherend to be subjected to the heating step can be used. The method of use of the masking film of the present invention is to attach the masking film to the surface of an adherend, The heating step is usually at 120°C or higher, preferably at 150°C or higher, and particularly preferably at 170°C or higher. and then peeling the heat-resistant adhesive masking film from the surface of the adherend. That's fine.

[0098] The heat-resistant adhesive masking film of the present invention can be peeled off from an adherend after use under high temperature conditions. When the adhesive is applied, it is difficult for the adhesive to remain on the adherend (the adhesive layer (adhesive) remains), etc. to become contaminated. The possibility of contamination during the manufacturing process of the masking film of the present invention is also reduced. The film is less likely to cause corrosion on metal substrates, so there is no risk of defects in the final product. is reduced. [Example]

[0099] The present invention will be explained in more detail below with reference to examples, but the present invention will not go beyond the gist of the invention. The present invention is not limited to the following examples unless otherwise specified. It means by weight. In the following examples, the weight average molecular weight, glass transition temperature, The acid value and the gel fraction of the adhesive were measured according to the methods described above.

[0100] <Production of polyester resin> In the following production examples, the total amount of carboxylic acids used in the esterification reaction is 1 mole. The ingredients were combined.

[0101] [Production of Polyester Resin (A-1)] A reactor equipped with a thermometer, a stirrer, a rectification column, and a nitrogen inlet tube was filled with dicarboxylic acids. 495 parts (0.9 moles) of benzoic acid (SebA), 45 parts (0.1 moles) of isophthalic acid (IPA) mol), 283 parts (1 mole) of neopentyl glycol (NPG) as polyol, 1, 6-hexanediol (1,6HG) 64 parts (0.2 moles), tetrabutyl tetani as a catalyst Add 0.3 parts of Tannate and heat up the internal temperature to 260°C over 2 hours. The esterification reaction was carried out for 3 hours. After that, the internal temperature is lowered to 170°C, and pyrometabolite is reacted with the acid anhydride of the trivalent or higher carboxylic acid. 113 parts (0.19 moles) of methyl acetic anhydride (PMAn) was added and the chain extension reaction was carried out for 1 hour. A polyester resin (A-1) was produced. The weight average molecular weight of the polyester resin (A-1) is 28,900, and the glass transition temperature is The temperature (Tg) was -32°C and the acid value was 70.1 mg KOH / g. %) is SebA / IPA / NPG / 1,6HG / PMAn=45.7 / 4.0 / 30. The product of the acid value and the weight average molecular weight was 2,025.89. It was 0.

[0102] [Production of Polyester Resin (A-2)] A reactor equipped with a thermometer, a stirrer, a rectification column, and a nitrogen inlet tube was filled with dicarboxylic acids. 543 parts (0.9 moles) of benzoic acid (SebA), 50 parts (0.1 moles) of isophthalic acid (IPA) mol), 286 parts (1 mole) of neopentyl glycol (NPG) as polyol, 1, 63 parts (0.2 moles) of 6-hexanediol (1,6HG), tetrabutyl thiol as a catalyst Add 0.3 parts of Tannate and heat up the internal temperature to 260°C over 2 hours. The esterification reaction was carried out for 3 hours. After that, the internal temperature is lowered to 170°C, and pyrometabolite is reacted with the acid anhydride of the trivalent or higher carboxylic acid. 59 parts (0.09 moles) of poly(methylamino)anhydride (PMAn) was added and a chain extension reaction was carried out for 1 hour. A polyester resin (A-2) was produced. The weight average molecular weight of the polyester resin (A-2) is 25,700, and the glass transition temperature is The temperature (Tg) was -42°C and the acid value was 49.0mgKOH / g. %) is SebA / IPA / NPG / 1,6HG / PMAn=51.1 / 4.5 / 31. The product of the acid value and the weight average molecular weight was 1,259,300. It was.

[0103] [Production of Polyester Resin (A-3)] In the production of the polyester resin (A-1), the internal temperature is lowered to 140°C to form a pyrometabolite. The polyester resin ( A-3) was produced. The weight average molecular weight of the polyester resin (A-3) is 5,500, and the glass transition temperature ( The Tg was -30°C and the acid value was 96 mgKOH / g. The product was 528,000.

[0104] [Production of Polyester Resin (A'-1)] A reactor equipped with a heater, thermometer, stirrer, rectification column, nitrogen inlet tube and vacuum device was installed. As dicarboxylic acids, 9.6 parts (0.2 moles) of isophthalic acid and 46.8 parts (0.2 moles) of sebacic acid parts (0.8 mol), and 27.1 parts (0.9 mol) of neopentyl glycol as polyol 1,4-butanediol 13.0 parts (0.5 moles), 1,6-hexanediol 3.0 parts (0.087 moles) and 0.5 parts (0.013 moles) of trimethylolpropane, catalyst 0.01 parts of tetrabutyl titanate was added as a starting material, and the internal temperature was gradually increased to 250°C. The esterification reaction was carried out over 4 hours. Then, the internal temperature was raised to 260°C, and 0.01 parts of tetrabutyl titanate was added as a catalyst. The mixture is charged, the pressure is reduced to 1.33 hPa, and the polymerization reaction is carried out for 3 hours to form a polyester resin. (A'-1) was produced. The weight average molecular weight of the resulting polyester resin (A'-1) was 70,000, and the glass transition temperature was 100°C. The temperature was -50°C and the acid value was 0.4 mg KOH / g. The product of this was 28,000.

[0105] <Production of Polyester Resin (A'-2)> A reactor equipped with a heater, thermometer, stirrer, rectification column, nitrogen inlet tube and vacuum device was installed. As the carboxylic acid, 680.6 parts (1.0 mole) of Pripol 1009, polyol As a catalyst, 319.4 parts (0.5 moles) of Pripol 2033, tetrabutyl Add 0.2 parts of titanate, gradually increase the internal temperature to 240°C, and let it cool for 4 hours. After that, the pressure was reduced to 1.33 hPa at an internal temperature of 240°C, and the reaction mixture was stirred for 3 hours. The esterification reaction was continued to produce a polyester resin (A'-2). The weight average molecular weight of the polyester resin (A'-2) is 4,340, and the glass transition temperature is The temperature was -45°C and the acid value was 66.6mgKOH / g. The final composition (%) was: Pripol 1009 / Pripol 2033 = 66.8 / 33.2. The product with the weight average molecular weight was 289,044.

[0106] <Production of Polyester-Based Pressure-Sensitive Adhesive Composition> The polyester resins (A-1) to (A-3) and (A'-2) obtained above were mixed with a metal A solution of ethyl ethyl ketone and 2-propanol (1:1) was used, each with a solids concentration of 50%. (A'-1) was diluted with ethyl acetate to a solids concentration of 50% and the resulting mixture was used in the following examples and It was used in the comparative examples.

[0107] [Example 1] For 100 parts of the solid content of the polyester resin (A-1) solution obtained above, 5 parts of methyl acrylate crosslinking agent (Mitsubishi Gas Chemical Company, Tetrad X), hindered phenol antioxidant 0.1 parts of adhesive (BASF, IRGANOX1010) were blended, and polyester adhesive was used. A composition was obtained. The obtained polyester-based pressure-sensitive adhesive composition was applied to a substrate so that the thickness after drying was about 50 μm. The coating was applied to a polyethylene terephthalate (PET) film (thickness 100 μm) as Then, the adhesive layer was dried at 100°C for 3 minutes to form an adhesive layer. The surface was protected by a treated PET film (release film), and the sample was placed in an atmosphere of 40°C. After aging for 10 days under atmospheric conditions, an adhesive film (heat-resistant adhesive film) was obtained.

[0108] [Examples 2 and 3] The adhesive filler was prepared in the same manner as in Example 1, except that the amount of crosslinking agent was changed as shown in Table 1. A heat-resistant adhesive film was obtained.

[0109] [Examples 4 to 8, Comparative Examples 1 to 3] The polyester resins shown in Table 1 were used, and the crosslinking agents were blended as shown in Table 1. An adhesive film (heat-resistant adhesive film) was obtained in the same manner as in Example 1, except for the above.

[0110] [Comparative Examples 4 and 5] For 100 parts of the solid content of the polyester resin (A'-1) solution obtained above, The amount of isocyanate crosslinking agent (Tosoh Corporation, Coronate HX) shown in An adhesive film (heat-resistant adhesive film) was prepared in the same manner as in Example 1, except that a terephthalate adhesive composition was obtained. (Mu) was obtained.

[0111] Using each of the obtained adhesive films (heat-resistant adhesive films), the gel fraction (%) of the adhesive was measured. The adhesive strength, contamination of the adherend and resistance to dents were evaluated as shown below. The results are shown in Table 1 below.

[0112] [Adhesive strength] SUS-BA and non-alkali glass were prepared as the adherends. After cutting the film (heat-resistant adhesive film) into 25 x 200 mm pieces under an environment of 23°C and 50% RH, Peel off the release film and place the adhesive layer on SUS-BA or non-alkali glass. Then, a 2 kg roller was moved back and forth to apply pressure to the film. After leaving the film in the same atmosphere for 30 minutes, Then, an autograph (Shimadzu Corporation, Autograph AGS-H 500N) was used to measure the peeling. The 180-degree peel strength (N / 25mm) was measured at a peel speed of 300mm / min, and the following criteria were met: Evaluated. ◎: 0.3N / 25mm or less. ○: Over 0.3N / 25mm and less than 0.5N / 25mm. ×: Exceeds 0.5N / 25mm.

[0113] [Heat-resistant adhesive strength] In the same manner as above, each adhesive film (heat-resistant adhesive film) was attached to each adherend. After storing in a 150°C incubator for 1 day (24 hours), the sample was stored in an environment of 23°C and 50% RH for 30 minutes. After leaving it to stand for 1 minute, the sample was analyzed using an autograph (Shimadzu Corporation, Autograph AGS-H 500N ) and measure the 180-degree peel strength (N / 25mm) at a peel speed of 300mm / min. The evaluation was based on the following criteria: ◎: 2.5N / 25mm or less. ○: Over 2.5N / 25mm and less than 10N / 25mm. ×:Exceeds 10N / 25mm.

[0114] [Adherent contamination] After measuring the heat-resistant adhesive strength, the adherend was visually inspected and evaluated for adhesive residue according to the following criteria: It was worth it. ○: No adhesive residue is visible. △: The mark where the sticker was applied is faintly visible. ×: Adhesive residue is clearly visible.

[0115] [Mark resistance] For each adhesive film (heat-resistant adhesive film) obtained, apply the adhesive film from the release film side. A 2 kg roller was rolled over the film, and the adhesive layer was visually observed and evaluated according to the following criteria: did. ○: No change. ×: Dents present.

[0116] [Table 1]

[0117] From the results in Table 1 above, it can be seen that the adhesive film of the present invention has a high adhesive strength when attached to an adherend. The adhesive strength is also low enough that it will not peel off from the substrate even when used in a high-temperature environment. It can be seen that the adhesive is less likely to remain on the adherend, causing contamination, and the heat-resistant adhesive strength is also low. Therefore, the polyester-based pressure-sensitive adhesive composition, polyester-based pressure-sensitive adhesive, and heat-resistant The pressure-sensitive adhesive composition for pressure-sensitive adhesive films is suitable as a pressure-sensitive adhesive layer for heat-resistant masking films. You will realize something. In contrast, the conventional products, Comparative Examples 1 to 3, had a pressure-sensitive adhesive layer that was too soft and could not be easily attached to the PET film. It is difficult to peel off or dents are left behind, and the adhesive strength is so strong that In particular, in Comparative Example 1, the release film was not peeled off smoothly. When the adhesive layer was forcibly peeled off, it failed cohesively, resulting in a decrease in adhesive strength and heat resistance. It was not possible to measure the adhesive strength. In addition, in Comparative Examples 4 and 5, the adhesive strength after heat resistance was The temperature increases too much, and both of these are unsuitable for use as a heat-resistant adhesive film. It was.

[0118] In addition, the above polyester resin (A-1) was used to prepare a resin having a solid content of 50%. The resulting polyester resin (A-1) solution was diluted with the dilution solvent shown in Table 2 to a solids content of 1 00 parts of an epoxy crosslinking agent (Tetrad X, manufactured by Mitsubishi Gas Chemical Company, Inc.) was added in the proportions shown in Table 2 below. The pot life of the mixture was evaluated based on the following criteria: The results are shown in Table 2 below. ○: No significant increase in viscosity was observed even after 2 hours of mixing. ×: Visible increase in viscosity observed within 2 hours after mixing.

[0119] [Table 2]

[0120] From the results in Table 2 above, it can be seen that the product diluted with methyl ethyl ketone alone has a poor pot life. By using 2-propanol, the pot life is improved. It becomes something like this. [Industrial Applicability]

[0121] The adhesive composition of the present invention has increased adhesive strength even when used in a high-temperature environment. Since there is little change over time in the properties such as the adhesive layer, it is suitable for use as an adhesive layer in heat-resistant adhesive films for masking. It is possible.

Claims

1. A polyester-based pressure-sensitive adhesive composition comprising a polyester-based resin having a product of acid value (mgKOH / g) and weight-average molecular weight of 1,000,000 to 100,000,000, and an epoxy-based crosslinking agent.

2. 2. The polyester-based pressure-sensitive adhesive composition according to claim 1, wherein the polyester-based resin has a glass transition temperature of -90 to 20°C.

3. 3. The polyester-based pressure-sensitive adhesive composition according to claim 1, wherein the polyester-based resin has an acid value of 5 mgKOH / g or more.

4. The polyester-based pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the polyester-based resin has a weight average molecular weight of 2,000 to 500,000.

5. A polyester-based pressure-sensitive adhesive obtained by crosslinking the polyester-based pressure-sensitive adhesive composition according to any one of claims 1 to 4.

6. 6. The polyester adhesive according to claim 5, wherein the polyester adhesive has a gel fraction of 70% by weight or more.

7. A pressure-sensitive adhesive film comprising a pressure-sensitive adhesive layer containing the polyester-based pressure-sensitive adhesive according to claim 5 or 6.

8. A pressure-sensitive adhesive composition for a heat-resistant adhesive film, comprising the polyester-based pressure-sensitive adhesive composition according to any one of claims 1 to 4.

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